Yes, you can pick them apart by
hindsight.
I already posted images which indicate that GT4's headlights are 3D modeled, and as far as I know,
all are modeled. And as for those modeled panel gaps in Forza, it doesn't show.
And this is the thing: on paper, Forza 2 is supposed to blow GT4 out of the water. If I post comparison shots, there shouldn't be any comparison. GT4 should look like tin foil and paper mache to Forza's glitter and gold. And like it or not, Forza 2 is just barely three years old now. It's a "this gen" game, and you can't say it isn't. GT4 is undeniably last gen, way last gen, on hardware next to last place in processing power. But it doesn't always look like it, not by a long shot.
What did Dan Greenawalt say? "Look at this car," and he points to the sports car zipping across the screen. "All of the surfaces are round and smooth. This generation isn't about polygons, Doug, it's about shaders."
Maybe Dan is more right than he knows: that it's not how many polygons you have, but it's what you do with them that counts. Here are a couple more of mine. The Forza Celica I painted won a competition.
I have a lot more to share, some images which you might not believe came unmodified from GT4.